Terminal: Performing DNS lookup for a domain

Question
How do I perform DNS lookup for a domain name?
Answer
The host command reads the DNS and returns the A, AAAA and MX records belonging to a name. This information is very useful at the start of a debugging session:
host yourdomain.tld
* replace yourdomain.tld with your actual domain name.
If the name is a redirect (CNAME) to another name, it will return the information for that other name. For example, www.openprovider.com is a redirect to openprovider.com:
host www.openprovider.com
If you want to see all record types, add the parameter -a:
host -a yourdomain.tld
* replace yourdomain.tld with your actual domain name.